全文获取类型
收费全文 | 880篇 |
免费 | 50篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 45篇 |
妇产科学 | 10篇 |
基础医学 | 102篇 |
口腔科学 | 27篇 |
临床医学 | 86篇 |
内科学 | 232篇 |
皮肤病学 | 20篇 |
神经病学 | 41篇 |
特种医学 | 142篇 |
外科学 | 70篇 |
综合类 | 12篇 |
预防医学 | 73篇 |
眼科学 | 3篇 |
药学 | 36篇 |
肿瘤学 | 43篇 |
出版年
2022年 | 3篇 |
2021年 | 13篇 |
2020年 | 3篇 |
2019年 | 9篇 |
2018年 | 16篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 22篇 |
2014年 | 20篇 |
2013年 | 30篇 |
2012年 | 27篇 |
2011年 | 33篇 |
2010年 | 23篇 |
2009年 | 42篇 |
2008年 | 24篇 |
2007年 | 43篇 |
2006年 | 40篇 |
2005年 | 28篇 |
2004年 | 24篇 |
2003年 | 20篇 |
2002年 | 23篇 |
2001年 | 27篇 |
2000年 | 20篇 |
1999年 | 22篇 |
1998年 | 56篇 |
1997年 | 47篇 |
1996年 | 24篇 |
1995年 | 29篇 |
1994年 | 15篇 |
1993年 | 18篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 20篇 |
1989年 | 16篇 |
1988年 | 21篇 |
1987年 | 20篇 |
1986年 | 15篇 |
1985年 | 17篇 |
1984年 | 11篇 |
1983年 | 13篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1977年 | 6篇 |
1976年 | 5篇 |
1975年 | 10篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 5篇 |
排序方式: 共有943条查询结果,搜索用时 15 毫秒
1.
BACKGROUND: There are obvious advantages to increasing donor retention. However, for reasons of blood safety, certain donors may, in fact, be more desirable to retain than others. “Safe” donors are defined as those who provided a blood donation that was negative on all laboratory screening tests and who subsequently reported no behavioral risks in response to an anonymous survey. This study identifies the most important factors affecting the intention of “safe” donors to provide another donation. STUDY DESIGN AND METHODS: An anonymous survey asking about donation history, sexual history, injecting drug use, and recent donation experience was mailed to 50,162 randomly selected allogeneic donors (including directed donors) who gave blood from April through July or from October through December 1993 at one of the five United States blood centers participating in the Retrovirus Epidemiology Donor Study. Before mailing, questionnaires were coded to designate donors with nonreactive laboratory screening tests at their most recent donation. RESULTS: A total of 34,726 donors (69%) responded, with substantially higher response among repeat donors. According to reported intentions only, the vast majority of “safe” donors indicated a high likelihood of donating again within the next 12 months. Only 3.4 percent reported a low likelihood of donating again. A comparison of those likely to return and those unlikely to return reveals significant differences in demographics and in ratings of the donation experience. A higher proportion of those unlikely to return were first-time donors, minority-group donors, and donors with less education. The highest projected loss among “safe” donors was seen for those who gave a fair to poor assessment of their treatment by blood center staff or of their physical well-being during or after donating. CONCLUSION: These data suggest that efforts to improve donors' perceptions of their donation experience, as well as attention to the physical effects of blood donation, may aid in the retention of both repeat and first-time donors. 相似文献
2.
I. Sioen † C. Matthys G. De Backer J. Van Camp† & S. De Henauw 《Journal of human nutrition and dietetics》2007,20(6):580-589
BACKGROUND: Regular seafood consumption is recommended in dietary guidelines. The aim of this study was to investigate the importance of seafood as a nutrient source in adolescents' diet and the extent to which seafood consumption can increase the intake of omega-3 polyunsaturated fatty acids and vitamin D. METHODS: Consumption data recorded during seven consecutive days for 341 adolescents selected in Ghent (Belgium) were used to estimate the intake of vitamin D, linoleic (LA), alpha-linolenic (LNA), arachidonic (AA), eicosapentaenoic (EPA), docosapentaenoic (DPA) and docosahexaenoic (DHA) acid. RESULTS: The adolescents consumed on average 3.21 microg/day vitamin D, 11.7 g/day LA and 1.4 g/day LNA. The mean intakes of AA, EPA, DPA and DHA were 83.2, 55.9, 18.4 and 111.4 mg/day respectively. The major source of vitamin D was fortified margarine. Fats and oils were the main sources for LA and LNA. The intake of AA was mainly contributed by meat, poultry and eggs. Fish and seafood contributed for 84.1%, 59.3% and 64.4% respectively for EPA, DPA and DHA. CONCLUSION: Flemish adolescents would benefit from increased seafood consumption, as this would lead to a higher intake of EPA and DHA as well as of vitamin D. Moreover, replacement of foods rich in saturated fat (SFA) by seafood products can help to reduce SFA intake. 相似文献
3.
Rosenberg ZS; Jahss MH; Noto AM; Shereff MJ; Cheung Y; Frey CC; Norman A 《Radiology》1988,167(2):489-493
Computed tomography (CT) was performed in 42 patients with 49 clinically suspected tears of the posterior tibial tendon. Twenty-eight of the 49 suspected tears were subsequently surgically explored and repaired. Three patterns of tendon abnormalities were recognized on CT scans: type I-intact, hypertrophied, heterogeneous tendon; type II-attenuated tendon; and type III-absence of a portion of a tendon. Types I and II correlated with partial rupture seen during surgery, and type III correlated with complete rupture of the tendon. CT findings were accurate in 96% of the patients who underwent surgery. In four cases (14%), tendon rupture was seen on CT scans, but the extent of the injury was underestimated and the rupture was misclassified. Reactive periostitis of the distal tibia was seen in 71% of diseased tendons and may represent an important factor in the diagnosis of tendon rupture. 相似文献
4.
Walter Matthys MD Han De Vries MS Ankie Hectors MS Maarten Veerbeek MS Willeke Heidemann MS Muriel Goud MS Jan A. R. van Hooff PhD Herman Van Engeland MD 《Child psychiatry and human development》1995,26(1):29-41
The behavior of conduct disordered (CD) children was compared with normal control (NC) children in interaction with normal
peers. Dyads consisting of a) a CD child and a normal peer and b) an NC child and the same normal peer as in a) were observed.
CD boys were less able than NC boys to neutralize incipient conflicts. Hitherto most behavioral studies of CD boys have concentrated
on their tendency to escalate conflicts but have paid very little attention to their difficulty in neutralizing conflicts. 相似文献
5.
Intestinal schistosomiasis japonica: CT-pathologic correlation 总被引:1,自引:0,他引:1
Lee RC; Chiang JH; Chou YH; Rubesin SE; Wu HP; Jeng WC; Hsu CC; Tiu CM; Chang T 《Radiology》1994,193(2):539
6.
7.
8.
9.
10.
Bilateral simultaneous tubal sextuplets: pregnancy after in-vitro fertilization--embryo transfer following salpingectomy 总被引:2,自引:1,他引:2
The presence of a damaged tube has been suggested in recent studies to have
a negative effect on in-vitro fertilization (IVF) outcome. Performing
bilateral salpingectomy prior to IVF to maximize pregnancy rates may also
result in unnecessary surgery. This case is also an example of the
occurrence of interstitial pregnancy after salpingectomy. This unusual type
of ectopic pregnancy must be kept in mind when evaluating a patient
suspected of a possible early abnormal gestation after assisted
reproductive technolologies.
相似文献